The purpose of this study is to determine if there is a relationship between fetal growth factors (leptin, tumor necrosis factor alpha, insulin, and c-peptide) and neonatal weight and body composition, in babies of women with gestational diabetes mellitus and those with normal glucose tolerance. This study will also investigate whether or not the placenta is a possible source of these growth factors. Additionally, neonatal blood at 48 hours of life will be examined to see if the baby continues to make these growth factors after birth.